Bulk cargo terminal positioning system and method based on Beidou / UWB fusion

Abstract

The invention relates to a bulk cargo terminal positioning system and method based on Beidou / UWB fusion. The positioning system comprises a space reference establishing module, a network formed by UWB positioning base stations, a mobile positioning terminal and a data fusion processing center. The positioning method comprises the following steps: S1, system initialization and reference establishment; s2, calibrating global coordinates of all base stations in the UWB positioning base station network by using the base station; s3, the mobile positioning terminal synchronously collects Beidou observation data, UWB ranging data and IMU data; and S4, the data fusion processing center carries out fusion calculation on the multi-source data, and outputs the real-time high-precision position of the mobile terminal in the unified global coordinate system. According to the invention, advantages of Beidou in an open area and strong terms of UWB in a shielding area are combined, continuous and stable positioning of the shielding area from outdoor to semi-outdoor is realized, no coverage blind area exists, and high precision and high reliability are realized.

Description

Technical Field

[0001] This invention relates to the technical field of high-precision positioning, and in particular to a positioning system and method for bulk cargo terminals based on BeiDou / UWB fusion. Background Technology

[0002] Bulk cargo terminals (such as coal, ore, and grain terminals) are critical nodes in port logistics, and their operational efficiency and safety levels directly affect the port's throughput capacity and economic benefits. At bulk cargo terminals, numerous mobile devices, such as gantry cranes, stacker-reclaimers, loaders, transport vehicles, and personnel, work collaboratively. Real-time, continuous, and high-precision positioning of these moving targets is fundamental to achieving automated scheduling, intelligent collision avoidance, operational process optimization, and safety management.

[0003] Currently, the commonly used positioning technologies at bulk cargo terminals mainly include:

[0004] GPS / BeiDou positioning: It can provide good absolute location information in open outdoor areas, but its signal is easily affected by obstruction and multipath effects. Near large machinery (such as cranes) at docks, inside warehouses, or at the edge of storage yards, satellite signals will be severely attenuated or even lost, resulting in inaccurate positioning or failure.

[0005] Ultra-wideband (UWB) positioning offers centimeter-level accuracy and strong resistance to multipath interference, making it ideal for indoor and heavily obstructed areas. However, its coverage is limited, requiring the deployment of numerous positioning base stations, resulting in high deployment and maintenance costs in the vast port area. Furthermore, UWB provides local coordinates relative to the base station, lacking absolute latitude and longitude information.

[0006] RFID and Bluetooth beacons are typically used for regional presence detection or rough positioning, but cannot meet the needs of high-precision continuous positioning.

[0007] LiDAR and visual SLAM are greatly affected by weather conditions (such as fog, rain, and dust), and their reliability decreases significantly in dusty bulk cargo terminal environments.

[0008] In conclusion, a single technology is insufficient to provide comprehensive, continuous, and reliable high-precision positioning in complex environments such as bulk cargo terminals, which are often semi-open and semi-closed and subject to severe electromagnetic interference. Therefore, there is an urgent need for a fusion positioning solution that integrates the advantages of multiple technologies, leveraging their strengths and compensating for their weaknesses. Summary of the Invention

[0009] The present invention aims to address the shortcomings of the prior art by providing a positioning system and method for bulk cargo terminals based on BeiDou / UWB fusion.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] The positioning system for bulk cargo terminals based on BeiDou / UWB fusion includes a spatial reference establishment module, a network of UWB positioning base stations, mobile positioning terminals, and a data fusion processing center.

[0012] Spatial reference establishment module: at least one, serving as the spatial reference source for the entire system, is formed by rigidly connecting a high-precision BeiDou receiver and a UWB positioning base station through rigid connectors, constituting a rigid body with known physical dimensions. The high-precision BeiDou receiver receives BeiDou satellite signals and calculates the absolute geodetic coordinates of its antenna phase center in real time, i.e., longitude B, latitude L, elevation H, or geocentric rectangular coordinates ECEF. Through the geometric relationship of the rigid connection, the absolute coordinates of the co-located UWB base station are accurately derived, establishing a unified, accurate, and dynamically maintained absolute coordinate reference for the entire port area.

[0013] The network composed of UWB positioning base stations: A cellular ranging network is formed by multiple UWB positioning base stations deployed in key areas of the dock. The global absolute coordinates of these base stations are transmitted and calibrated through the spatial reference establishment module, so that the entire UWB network is unified under a global coordinate system consistent with BeiDou.

[0014] Mobile positioning terminal: one or more, installed on mobile devices that require positioning, each terminal integrating a Beidou positioning module, a UWB positioning tag and a data communication module;

[0015] Data Fusion Processing Center: This center receives and fuses reference maintenance data from the spatial reference establishment module, base station coordinates and tag ranging information from the UWB positioning base station network, and BeiDou observations and UWB ranging values ​​from mobile positioning terminals. The data fusion processing center runs a fusion positioning solution engine, which uses fusion algorithms to calculate in real time the high-precision position, velocity, and attitude information of each mobile terminal in a unified global coordinate system.

[0016] Key areas of the dock include lampposts and building rooftops.

[0017] The BeiDou positioning module is used to receive BeiDou satellite signals, output raw pseudorange, carrier phase observations and navigation messages, and can calculate the local position accuracy factor (PDOP) and the number of visible satellites.

[0018] UWB positioning tags are used for two-way communication and precise ranging with the UWB positioning base station network;

[0019] The data communication module is used to transmit observation data uplink to the data fusion processing center.

[0020] The data fusion processing center includes a fusion positioning solution engine that employs an improved adaptive Kalman filter algorithm. The algorithm's observation noise covariance matrix R is not a fixed constant, but a time-varying matrix R(k) that can be dynamically and adaptively adjusted based on the following factors:

[0021] BeiDou signal quality indicators: including the number of visible satellites N sat And position accuracy factor PDOP, when N sat When the signal quality is less than the preset threshold or the PDOP is higher than the preset threshold, the system determines that the BeiDou signal quality is poor and increases the noise variance of the BeiDou observations accordingly.

[0022] NLOS (Non-Line-of-Sight) Identification of UWB Signals: By analyzing the arrival time, angle of arrival, or channel impulse response characteristics of UWB signals, NLOS propagation paths are identified. Once identified as NLOS, the noise variance of the UWB ranging value is increased to reduce its weight in the fusion solution.

[0023] The BeiDou signal quality indicators also include the carrier noise density ratio (C / N0) and cycle slip detection flags. When C / N0 is below a certain threshold or a cycle slip is detected, the observation noise covariance will also be adjusted.

[0024] The mobile positioning terminal also integrates an inertial measurement unit (IMU), which includes at least a three-axis accelerometer and a three-axis gyroscope. The IMU data is sent together to the data fusion processing center to perform tightly coupled dead reckoning when both BeiDou satellite signals and UWB signals are temporarily unavailable. This is closely integrated with the prediction stage of the filter to maintain positioning continuity for a short period of time and suppress the cumulative error of pure inertial navigation.

[0025] The positioning method of the above-mentioned positioning system for bulk cargo terminals based on BeiDou / UWB fusion includes the following steps:

[0026] S1. System initialization and benchmark establishment: Start the space benchmark establishment module to enable the high-precision Beidou receiver to enter a stable working state. Through long-term observation or access to the CORS network, accurately determine its position as the global coordinate origin or a known point.

[0027] S2. Using the base station, determine the global coordinates of all base stations in the UWB positioning base station network;

[0028] S3. The mobile positioning terminal synchronously collects BeiDou observation data, UWB ranging data, and IMU data.

[0029] S4. The data fusion processing center fuses and calculates multi-source data to output the real-time high-precision position of the mobile terminal in a unified global coordinate system.

[0030] The beneficial effects of this invention are: This invention combines the advantages of BeiDou in open areas and the strengths of UWB in obstructed areas, achieving continuous and stable positioning from outdoor to semi-outdoor and obstructed areas, with no coverage blind spots, high precision and high reliability, and better adaptability to harsh working conditions such as dust, humidity and electromagnetic interference commonly found in bulk cargo terminals. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the positioning system in this invention;

[0032] Figure 2 This is a flowchart illustrating the positioning method in this invention.

[0033] The following will describe in detail, with reference to the accompanying drawings, embodiments of the present invention. Detailed Implementation

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0037] Positioning systems for bulk cargo terminals based on BeiDou / UWB fusion, such as Figure 1 As shown, it includes a spatial reference establishment module, a network consisting of UWB positioning base stations, a mobile positioning terminal, and a data fusion processing center.

[0038] Spatial reference establishment module: at least one, serving as the spatial reference source for the entire system, is formed by rigidly connecting a high-precision BeiDou receiver (e.g., a BeiDou three-star or higher frequency receiver) and a UWB positioning base station through rigid connectors, constituting a rigid body with known physical dimensions. The high-precision BeiDou receiver receives BeiDou satellite signals and calculates the absolute geodetic coordinates of its antenna phase center in real time, i.e., longitude B, latitude L, elevation H, or geocentric rectangular coordinates ECEF. Through the geometric relationship of the rigid connection, the absolute coordinates of the co-located UWB base station are accurately derived, establishing a unified, accurate, and dynamically maintained absolute coordinate reference for the entire port area.

[0039] The network consisting of UWB positioning base stations: A cellular ranging network is formed by multiple UWB positioning base stations deployed in key areas of the dock (such as street lamp poles and building rooftops). The global absolute coordinates of these base stations are transmitted and calibrated through a spatial reference establishment module, so that the entire UWB network is unified under a global coordinate system consistent with BeiDou.

[0040] Mobile positioning terminal: one or more, installed on mobile devices that require positioning. Each terminal integrates a Beidou positioning module, a UWB positioning tag, and a data communication module.

[0041] The BeiDou positioning module is used to receive BeiDou satellite signals, output raw pseudorange, carrier phase observations and navigation messages, and can calculate the local position accuracy factor (PDOP) and the number of visible satellites.

[0042] UWB positioning tags are used for two-way communication and precise ranging with the UWB positioning base station network;

[0043] The data communication module is used to transmit observation data uplink to the data fusion processing center.

[0044] The mobile positioning terminal also integrates an inertial measurement unit (IMU), which includes at least a three-axis accelerometer and a three-axis gyroscope. The IMU data is sent together to the data fusion processing center to perform tightly coupled dead reckoning when both BeiDou satellite signals and UWB signals are temporarily unavailable (e.g., when a vehicle enters a completely enclosed warehouse). This is closely integrated with the prediction stage of the filter to maintain positioning continuity for a short period of time and suppress the cumulative error of pure inertial navigation.

[0045] Data Fusion Processing Center: This center receives and fuses reference maintenance data from the spatial reference establishment module, base station coordinates and tag ranging information from the UWB positioning base station network, and BeiDou observations and UWB ranging values ​​from mobile positioning terminals. The data fusion processing center runs a fusion positioning solution engine, which uses fusion algorithms to calculate in real time the high-precision position, velocity, and attitude information of each mobile terminal in a unified global coordinate system.

[0046] The data fusion processing center includes a fusion positioning solution engine that employs an improved adaptive Kalman filter algorithm. The algorithm's observation noise covariance matrix R is not a fixed constant, but a time-varying matrix R(k) that can be dynamically and adaptively adjusted based on the following factors:

[0047] BeiDou signal quality indicators: including the number of visible satellites N sat And position accuracy factor PDOP, when N sat When the signal quality is less than the preset threshold or the PDOP is higher than the preset threshold, the system determines that the BeiDou signal quality is poor and increases the noise variance of the BeiDou observations accordingly.

[0048] The BeiDou signal quality indicators also include the carrier noise density ratio C / N0 and cycle slip detection flags. When C / N0 is below a certain threshold or a cycle slip is detected, the observation noise covariance will also be adjusted.

[0049] NLOS (Non-Line-of-Sight) Identification of UWB Signals: By analyzing the arrival time, angle of arrival, or channel impulse response characteristics of UWB signals, NLOS propagation paths are identified. Once identified as NLOS, the noise variance of the UWB ranging value is increased to reduce its weight in the fusion solution.

[0050] The positioning method of the above-mentioned positioning system for bulk cargo terminals based on BeiDou / UWB fusion, such as... Figure 2 As shown, it includes the following steps:

[0051] S1. System Initialization and Reference Establishment: Start the space reference establishment module to enable the high-precision Beidou receiver to enter a stable working state. Through long-term observation or access to the CORS network, accurately determine its position as the global coordinate origin or a known point.

[0052] S2. Using the base station, determine the global coordinates of all base stations in the UWB positioning base station network;

[0053] The UWB tag integrated with the base station is used as a moving beacon with known absolute coordinates;

[0054] By controlling the mobile beacon or utilizing its normal signal, multiple UWB ranging measurements are performed with each base station in the UWB positioning base station network that needs to be calibrated, obtaining a set of distance observation values ​​ρ. i base , where i is the base station index;

[0055] For the i-th UWB base station, its unknown coordinates are (X... i ,Y i Z i Given the beacon coordinates (X... b ,Y b Z b Then the following observation equations exist:

[0056] ;

[0057] Where c is the speed of light, δt is the clock error, and ϵ i To observe noise;

[0058] By employing the principle of spatial resection and combining the observation equations for ranging at at least three different locations, the absolute coordinates (X, Y, F) of each UWB base station are calculated using the least squares method or a filtering algorithm. i ,Y i Z i ).

[0059] S3. The mobile positioning terminal synchronously collects BeiDou observation data, UWB ranging data, and IMU data.

[0060] During operation, the mobile positioning terminal synchronously collects the following data and adds a unified timestamp:

[0061] BeiDou raw observation data, for the j-th satellite: pseudorange carrier phase ;

[0062] UWB ranging data: To the k-th UWB base station;

[0063] Raw IMU data: Triaxial acceleration a raw and triaxial angular velocity ω raw .

[0064] S4. The data fusion processing center fuses and calculates multi-source data to output the real-time high-precision position of the mobile terminal in a unified global coordinate system.

[0065] The fusion solution steps specifically include:

[0066] S41. Establish a state equation with terminal position, velocity, and clock error as state variables;

[0067] Define the state vector X of the Kalman filter as:

[0068] ;

[0069] in:

[0070] r and v are the position and velocity of the terminal in the global coordinate system; a b and ω b The zero bias of the IMU accelerometer and gyroscope is considered as a random walk process; δt and δf are the clock bias and clock drift of the Beidou receiver.

[0071] The state equations are discretized as follows:

[0072] ;

[0073] in:

[0074] Φ k,k−1 W is the state transition matrix, derived from Newtonian mechanics and the IMU error model. k−1 This is process noise;

[0075] S42. Establish a fusion observation equation that simultaneously includes the BeiDou observation model and the UWB observation model;

[0076] The observation vector Z contains all observations from BeiDou and UWB;

[0077] ;

[0078] BeiDou observation model, for the j-th satellite:

[0079] ;

[0080] in:

[0081] For satellite position; I j and T j These are the ionospheric and tropospheric delays, respectively. To observe noise;

[0082] UWB observation model, for the k-th base station:

[0083] ;

[0084] in:

[0085] The coordinates of the already calibrated base stations; The observation noise is represented by the linearized observation equation as follows:

[0086] ;

[0087] in:

[0088] H k V is the observation matrix; k The covariance matrix of the observed noise is R(k);

[0089] S43. Run the adaptive Kalman filter to dynamically allocate the weights of BeiDou and UWB observations based on the real-time signal quality and make the optimal estimate.

[0090] predict: ;

[0091] Covariance prediction: ;

[0092] Adaptive calculation of observation noise covariance R(k):

[0093] For the BeiDou observation value j, the corresponding Based on the current PDOP(k) and N sat (k) Dynamic calculation;

[0094] For a UWB observation k, if it is identified as NLOS, then ,otherwise ;

[0095] Kalman gain calculation: ;

[0096] Status Update: ;

[0097] Covariance update: . Specific Implementation Example 1:

[0099] This positioning system has been deployed at a large coal export terminal.

[0100] Base station: A base station is set up on the roof of the dock office building. Its Beidou receiver is connected to the port area CORS network to obtain absolute coordinates with centimeter-level accuracy.

[0101] UWB base stations: A total of 15 UWB base stations were deployed on the crossbeams of the two gantry cranes, the roof of the transfer station, and the lighthouse at the boundary of the yard to ensure effective coverage of the yard, loading and unloading points, and roads.

[0102] Mobile terminals: Integrated Beidou / UWB mobile positioning terminals were provided for 5 gantry cranes, 10 stacker-reclaimers, 30 dump trucks and 50 on-site inspection personnel.

[0103] System Operation: The data fusion and processing center is deployed in the central control room of the dock. After the system was operational, the global coordinate calibration of all UWB base stations was first completed using the reference station.

[0104] Results: After the system was put into use, the positioning trajectories of trucks traveling in open yards and loaders operating under gantry cranes were continuous and smooth, with no missed points throughout the entire process. Positioning accuracy: Better than 10 cm in open areas (BeiDou dominant); better than 30 cm in severely obscured areas (UWB dominant). This data has been successfully applied to automated stacking and reclaiming, intelligent vehicle scheduling, and active safety protection systems for personnel, significantly improving terminal operation efficiency and safety management.

[0105] This invention has the following advantages:

[0106] 1. Seamless full coverage: Combining the advantages of BeiDou in open areas and the strengths of UWB in obstructed areas, it achieves continuous and stable positioning from outdoor to semi-outdoor and obstructed areas, with no coverage blind spots.

[0107] 2. High precision and high reliability: Through deep fusion algorithms, even when the performance of a single technology degrades, it can be compensated for by another technology, ensuring the accuracy and reliability of the positioning results. The overall positioning accuracy can reach the centimeter level to the sub-meter level.

[0108] 3. Unified absolute coordinates: By cleverly integrating the UWB local coordinate system with the BeiDou global coordinate system through the base station, all positioning targets output standard latitude, longitude and altitude coordinates, which facilitates seamless integration with GIS maps and dispatch systems.

[0109] 4. Enhanced environmental adaptability: It is better adapted to harsh working conditions commonly encountered at bulk cargo terminals, such as dust, humidity, and electromagnetic interference. UWB has strong multipath resistance, and BeiDou is unaffected by dust in open areas.

[0110] 5. Cost and performance balance: Compared with deploying high-density UWB base stations throughout the entire area, this solution only deploys UWB base stations in key areas, utilizing BeiDou coverage in open areas, effectively controlling system construction and maintenance costs while ensuring performance.

[0111] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or direct application to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A positioning system for bulk cargo terminals based on BeiDou / UWB fusion, characterized in that, This includes a spatial reference establishment module, a network consisting of UWB positioning base stations, mobile positioning terminals, and a data fusion processing center; Spatial reference establishment module: at least one, serving as the spatial reference source for the entire system, is formed by rigidly connecting a high-precision BeiDou receiver and a UWB positioning base station through rigid connectors, constituting a rigid body with known physical dimensions. The high-precision BeiDou receiver receives BeiDou satellite signals and calculates the absolute geodetic coordinates of its antenna phase center in real time, i.e., longitude B, latitude L, elevation H, or geocentric rectangular coordinates ECEF. Through the geometric relationship of the rigid connection, the absolute coordinates of the co-located UWB base station are accurately derived, establishing a unified, accurate, and dynamically maintained absolute coordinate reference for the entire port area. The network composed of UWB positioning base stations: A cellular ranging network is formed by multiple UWB positioning base stations deployed in key areas of the dock. The global absolute coordinates of these base stations are transmitted and calibrated through the spatial reference establishment module, so that the entire UWB network is unified under a global coordinate system consistent with BeiDou. Mobile positioning terminal: one or more, installed on mobile devices that require positioning, each terminal integrating a Beidou positioning module, a UWB positioning tag and a data communication module; Data Fusion Processing Center: This center receives and fuses reference maintenance data from the spatial reference establishment module, base station coordinates and tag ranging information from the UWB positioning base station network, and BeiDou observations and UWB ranging values ​​from mobile positioning terminals. The data fusion processing center runs a fusion positioning solution engine, which uses fusion algorithms to calculate in real time the high-precision position, velocity, and attitude information of each mobile terminal in a unified global coordinate system.

2. The positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 1, characterized in that, Key areas of the dock include lampposts and building rooftops.

3. The positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 1, characterized in that, The BeiDou positioning module is used to receive BeiDou satellite signals, output raw pseudorange, carrier phase observations and navigation messages, and can calculate the local position accuracy factor (PDOP) and the number of visible satellites. UWB positioning tags are used for two-way communication and precise ranging with the UWB positioning base station network; The data communication module is used to transmit observation data uplink to the data fusion processing center.

4. The positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 1, characterized in that, The data fusion processing center includes a fusion positioning solution engine that employs an improved adaptive Kalman filter algorithm. The algorithm's observation noise covariance matrix R is not a fixed constant, but a time-varying matrix R(k) that can be dynamically and adaptively adjusted based on the following factors: BeiDou signal quality indicators: including the number of visible satellites N sat And position accuracy factor PDOP, when N sat When the signal quality is less than the preset threshold or the PDOP is higher than the preset threshold, the system determines that the BeiDou signal quality is poor and increases the noise variance of the BeiDou observations accordingly. NLOS (Non-Line-of-Sight) Identification of UWB Signals: By analyzing the arrival time, angle of arrival, or channel impulse response characteristics of UWB signals, NLOS propagation paths are identified. Once identified as NLOS, the noise variance of the UWB ranging value is increased to reduce its weight in the fusion solution.

5. The positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 4, characterized in that, The BeiDou signal quality indicators also include the carrier noise density ratio (C / N0) and cycle slip detection flags. When C / N0 is below a certain threshold or a cycle slip is detected, the observation noise covariance will also be adjusted.

6. The positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 1, characterized in that, The mobile positioning terminal also integrates an inertial measurement unit (IMU), which includes at least a three-axis accelerometer and a three-axis gyroscope. The IMU data is sent together to the data fusion processing center to perform tightly coupled dead reckoning when both BeiDou satellite signals and UWB signals are temporarily unavailable. This is closely integrated with the prediction stage of the filter to maintain positioning continuity for a short period of time and suppress the cumulative error of pure inertial navigation.

7. The positioning method for a bulk cargo terminal positioning system based on BeiDou / UWB fusion according to any one of claims 1-6, characterized in that, Includes the following steps: S1. System initialization and benchmark establishment: Start the space benchmark establishment module to enable the high-precision Beidou receiver to enter a stable working state. Through long-term observation or access to the CORS network, accurately determine its position as the global coordinate origin or a known point. S2. Using the base station, determine the global coordinates of all base stations in the UWB positioning base station network; S3. The mobile positioning terminal synchronously collects BeiDou observation data, UWB ranging data, and IMU data. S4. The data fusion processing center fuses and calculates multi-source data to output the real-time high-precision position of the mobile terminal in a unified global coordinate system.

8. The positioning method of the positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 7, characterized in that, In step S2, the specific steps for calibrating the global coordinates of the UWB positioning base station network are as follows: The UWB tag integrated with the base station is used as a moving beacon with known absolute coordinates; By controlling the mobile beacon or utilizing its normal signal, multiple UWB ranging measurements are performed with each base station in the UWB positioning base station network that needs to be calibrated, obtaining a set of distance observation values ​​ρ. i base , where i is the base station index; For the i-th UWB base station, its unknown coordinates are (X... i ,Y i Z i Given the beacon coordinates (X... b ,Y b Z b Then the following observation equations exist: ； Where c is the speed of light, δt is the clock error, and ϵ i To observe noise; By employing the principle of spatial resection and combining the observation equations for ranging at at least three different locations, the absolute coordinates (X, Y, F) of each UWB base station are calculated using the least squares method or a filtering algorithm. i ,Y i Z i ).

9. The positioning method of the positioning system for bulk cargo terminals based on BeiDou / UWB fusion as described in claim 8, characterized in that, In step S3, the mobile positioning terminal synchronously collects the following data and adds a unified timestamp during the operation: BeiDou raw observation data, for the j-th satellite: pseudorange carrier phase ; UWB ranging data: To the k-th UWB base station; Raw IMU data: Triaxial acceleration a raw and triaxial angular velocity ω raw .

10. The positioning method of the positioning system for bulk cargo terminals based on BeiDou / UWB fusion according to claim 9, characterized in that, In step S4, the fusion solution step specifically includes: S41. Establish a state equation with terminal position, velocity, and clock error as state variables; Define the state vector X of the Kalman filter as: ； in: r and v are the position and velocity of the terminal in the global coordinate system; a b and ω b The zero bias of the IMU accelerometer and gyroscope is considered as a random walk process; δt and δf are the clock bias and clock drift of the Beidou receiver. The state equations are discretized as follows: ； in: Φ k,k−1 W is the state transition matrix, derived from Newtonian mechanics and the IMU error model. k−1 This is process noise; S42. Establish a fusion observation equation that simultaneously includes the BeiDou observation model and the UWB observation model; The observation vector Z contains all observations from BeiDou and UWB; ； BeiDou observation model, for the j-th satellite: ； in: For satellite position; I j and T j These are the ionospheric and tropospheric delays, respectively. To observe noise; UWB observation model, for the k-th base station: ； in: The coordinates of the already calibrated base stations; The observation noise is represented by the linearized observation equation as follows: ； in: H k V is the observation matrix; k The covariance matrix of the observed noise is R(k); S43. Run the adaptive Kalman filter to dynamically allocate the weights of BeiDou and UWB observations based on the real-time signal quality and make the optimal estimate. predict: ; Covariance prediction: ; Adaptive calculation of observation noise covariance R(k): For the BeiDou observation value j, the corresponding Based on the current PDOP(k) and N sat (k) Dynamic calculation; For a UWB observation k, if it is identified as NLOS, then ,otherwise ; Kalman gain calculation: ; Status Update: ; Covariance update: .

Images